And more than one mixing service shut down/seized by the government but it's not simply because they are operating but it is because the government traced that the platform is used to launder the hacked funds from other event, and they can claim such a thing with any mixer if they want to.
What do you mean by physical exchange? You mean trading with someone in person or Bitcoin ATMs?
A physical exchange is basically a shop where they trade it for you. It's very common service in my area.
You want to sell some bitcoin? They generate an exchange address for you, you send bitcoin there and when there's a confirmation they give you cash. It usually takes up to 20 minutes and there's a no KYC to a certain limit.
The most important thing for me is that the money doesn't go through a bank, so there's no trace you've ever traded anything. Also, they will never seize your coins or anything like that.